This is because of the way that the electrons in an atom of iron behave. The electrons in an iron atom tend to have the ability to align themselves and face one toward one direction such that one side of the atom has high negative charge and the other side has a high positive charge. So then that atom will behave like a tiny magnet.
Now when many of these "tiny magnets" line up, their combined attraction creates the force known as magnetism.
Most other elements do not have this unique property that iron has and that is why they are not magnetic.
The genetic material is identical in asexual reproduction- in order for organisms to be strong they need variety so if a disease comes, some of the species may be able to fight it off because of their varied genetics
It does not violate the law of conservation of energy. The oscillation stops when the energy is lost and the energy is lost because it becomes heat that is created by the air resistance and many other forces found in the surrounding of the oscillating spring.
